Blade for snowplows and similar devices



Sept. 9, 1969 T E. T. MEYER BLADE FOR SNOWPLOWS AND SIMILAR DEVICESFiled Nov. 18. 1966 FIG. I

EDWARD T. MEYER May, 746% 8 8x14,

ATTORNEYS I United States Patent 3,465,456 BLADE FOR SNOWPLOWS ANDSIMILAR DEVICES Edward T. Meyer, Shaker Heights, Ohio, assiguor to MeyerProducts, Inc., Cleveland, Ohio Filed Nov. 18, 1966, Ser. No. 595,470Int. Cl. EOlh 5/06, 5/04 US. CI. 3750 3 Claims ABSTRACT OF THEDISCLOSURE A snowplow of the like includes a moldboard having a cuttingedge of elastomeric material attached to the lower edge thereof. Theelastomeric cutting edge slopes downwardly and forwardly from the loweredge of the moldboard and is sufiiciently rigid to stay in its staticposition when subjected to horizontal forces defined by friction andloose material being plowed. The elastomeric cutting edge issufficiently flexible to bend backwardly when striking a substantiallyimmovable object projecting up from a roadway.

The present invention pertains to the art of plows to clear snow andother debris from roadways and similar surfaces, and more particularlyto an improved blade for snowplows and similar devices.

The invention is particularly applicable to a blade which is used toplow or remove snow from a roadway, and it will be described withparticular reference thereto; however, it will be appreciated that theinvention has much broader applications and may be used for blades whichperform other functions, such as clearing or removing miscellaneousmaterials from a generally planar surface.

A plow of the type used to remove snow from a roadway m-ust include ablade which first moves the snow upwardly and then rolls it transverselyaway from the plow. To accomplish this, the blade includes a bodyportion having a curvilinear configuration which terminates in .a lowerplowing edge. The plowing edge usually extends in a forward directionand, in effect, digs into the snow and forces the snow onto thecurvilinear body of the blade. The contour of this body portion impartsa rolling action to the upwardly moving snow and forces the snowtransversely across the face of the blade and to the side of the plow.For efiicient plowing action, the lower plowing edge must be as close aspossible to the surface of the roadway. Otherwise, a layer of snowremains on the roadway, and subsequent removal operations are required.Maintaining the plowing edge of the blade close to the roadway has onedistinct disadvantage. The plowing edge often collides withobstructions, such as upwardly extending manhole covers and protrudingfaults in the roadway. At one time these collisions caused damage to thesnowplow and sometimes even injured persons operating the plow. Thishazard has been generally overcome by subsequent developments in the artof manufacturing snowplows.

A number of years ago, a snowplow blade was developed which included alowermost plowing edge that included in a rearward direction. As theblade was being used to remove snow, the snow would build up and compactitself in the cavity created at the front of the plowing edge by theinclination of the plowing edge. This build up of snow formed aneffective plowing wedge which forced the snow upwardly onto thecurvilinear body of the blade. When this type of blade contacted anobstruction in the roadway, the rearward inclination of the plowing edgeraised the blade over the obstruction and prevented the difiiculties andhazards resulting from a direct collision with such obstructions.However,

3,465,456 Patented Sept. 9, 1969 when the blade was raised, it did notplow. For this reason, ridges of snow were left in the roadway atvarious intervals. This type of plowing blade had another disadvantage.As the snow built up and compacted under the blade it also tended towedge the blade upwardly. Consequently, the effective plowing positionof the blade continued to raise until efficient removal of snow from aroadway was impaired.

To overcome the above-mentioned difficulty of gradually raising thesnowplowing blade as snow built up and compacted under the blade, itbecomes somewhat common practice to provide a pivoted lower plowingsection on the blade, with the lower edge of the plowing section facingforwardly. An obstruction in the roadway tripped the lower pivotedplowing section and ridges of snow deposits were left on the roadway.-In addition, the tripping force was relatively high since a substantialforce was required to cause the plowing section to trip backwardly. Thetripping section was below the mounting point of the blade; therefore,the tripping force was multiplied at the blade mounting point, andrelatively high stresses were created on the structural members used toamount the blade onto an appropriate vehicle. This latter-mentioneddisadvantage was substantially eliminated by providing a snow plowingblade wherein the whole blade tripped. In this manner, the trippingpoint was aligned with the blade mounting point to reduce transmittedforces and stresses on the mounting structure during tripping of thesnowplow. This latter type of snowplow blade is now in general use;however, it requires a somewhat expensive tripping mechanism, and itstill leaves ridges of snow when the plow is tripped by a roadwayobstruction. In addition, it has been found that the blade can, in rareinstances, remove a manhole cover instead of tripping over the cover.When this happens, a relatively large, and potentially dangerous,opening is left in the roadway. Another vehicle travelling behind thesnowplow could conceivably drop into the open manhole, although noactual instances of this are known.

It has been suggested that a snowplow having a tripping mechanism couldbe provided with a strip of rubber along the plowing edge; however, thisconstruction exhibits serious disadvantages, and it does not efficientlyremove snow from a roadway. When the weight of the blade, which isgenerally 50-75 pounds per linear foot of plowing edge, is imposed uponthe lower rubber strip, the rubber strip collapses. Thus, the blade mustbe held up by appropriately positioned shoes riding along the roadway.During plowing with this type of blade, the rubber strip foldsbackwardly and acts as a squeegee. This, in essence, forms a backwardlyinclined plowing edge similar to one of the previously discussed plowingblades. Snow removal is effected by an accumulation of compacted snow infront of the rubber blade which forms a plowing edge. As mentionedbefore, accumulation of snow in a cavity forward of a backwardly orvertically inclined plowing edge gradually raises the blade and preventseffircient plowing of snow. Thus, this rubber strip on the plowing edgeof a tripping plow exhibits the saline disadvantages of previouslydescribed prior snowplowing blades, although such a blade does allowcertain obstructions to be passed without tripping the blade or raisingthe blade. In addition, a rubber strip on the plowing edge of a snowplowblade becomes brittle in cold weather and deteriorates from exposure tolight and oil.

These rubber strips on the plowing edge of a blade are always used in avertical position or in a backwardly inclined position. Consequently, ablade with a rubber strip has been used only for the purpose of allowingthe blade to pass over obstructions without regard to the seriouslimitations which a backwardly folded plowing edge presents in theactual plowing of snow. The inherent characteristics of rubber dictatethat only a squeegee type of action can be accomplished. This squeegeeaction, which is contemplated by these rubber edged blades, causesvibration of the blade in a vertical direction during snow plowing. Thisresults in a washboard plowed surface which, of course, isunsatisfactory. A rubber edged snowplow is illustrated in Brochure No.82l947694, dated of The Goodyear Tire and Rubber Company of Akron, June1966 and pubilshed by Industrial Products Division Ohio. The presentinvention as defined later was invented before this article waspublished; therefore, a discussion of this article, or the bladedisclosed therein, is not intended to admit that either is statutoryprior art.

The present invention is directed toward an improved blade for snowplowsor similar devices which blade overcomes the various difficultiesdiscussed in the previous paragraphs.

In accordance with the present invention, there is provided animprovement in a snowplow blade of the type used to clear snow anddebris from roadways and similar surfaces, which blade includes agenerally curvilinear body portion terminating in a lower, generallystraight plowing edge portion. This improvement comprises forming theplowing edge portion of the blade from an elongated strip of plasticmaterial having a front surface, a rear surface, a top edge portion, anda bottom edge portion, and means for securing the top edge portion ontothe body portion with the bottom edge portion of the strip forming thesurface engaging plowing edge for the blade. The plastic material,contemplated by the present invention, has a sufiicient flexibility andmemory to allow at least a 90 backward deflection of the strip at -20 F.with substantially complete recovery and sufliciently rigid to supportat least 50 pounds per linear foot of the strip during normal,unobstructed plowing with less than approximately 10 backward deflectionof the strip.

Stated another way, the plastic strip is formed from a material havingsuflicient rigidity to allow only a slight deflection of the strip asthe weight of the blade is imposed thereon and a suflicient flexibilityto allow the strip to deflect as the blade passes over an obstruction ina roadway.

In accordance with the preferred embodiment of the present invention,the plastic material supported on the lower end of the snowplowing bladeis formed from a cast polyurethane having a hardness of approximately90-95 durometers.

By constructing a snowplow blade in accordance with the inventiondescribed above, the plastic material forms and retains an outwardlyextending plowing edge quite analogous to a steel edge, during normalplowing, which function is not possible, or even contemplated, by ablade formed from rubber wherein the blade folds backwardly and acts asa squeegee. During normal plowing means plowing on a surface having noupwardly projecting obstructions.

The primary object of the present invention is the provision of animproved blade of the type used to remove snow and debris from a roadwayor a similar surface, which blade is relatively simple to produce andinstall and is durable in use.

Another object of the present invention is the provision of an improvedblade of the type used to remove snow and debris from a roadway or asimilar surface, which blade includes a plowing edge formed from aplastic material that holds an outward disposition during normal plowingand flexes backwardly upon striking an obstruction in the roadway.

Still another object of the present invention is the provision of animproved blade, of the type described above, which blade is formed froma cast polyurethane.

Still another object of the present invention is the provision of animproved blade, of the type described above, which blade passes overobstructions without tripping the blade backwardly and, thus, leavingunplowed ridges of snow. Accordingly, in normal situations, the trippingmechanism may be eliminated.

These and other objects and advantages will become apparent from thefollowing description used to illustrate the preferred embodiment of theinvention as read in connection with the accompanying drawing in which:

FIGURE 1 is a side elevational view showing, somewhat schematically, insolid lines a blade constructed in accordance with the present inventionand in phantom lines certain auxiliary equipment associated with theblade;

FIGURE 2 is a partial schematic view illustrating two blades of whichthe present invention is an improvement;

FIGURE 3 is an enlarged partially cross-sectioned view taken generallyalong line 33 of FIGURE 1;

FIGURE 4 is an enlarged cross-sectional view, similar to FIGURE 3,showing an operating characteristic of the present invention;

FIGURE 5 is a schematic view illustrating certain geometricalrelationships of the present invention;

FIGURE 6 is a front elevational view illustrating the preferredembodiment of the present invention as it passes over an obstruction;and,

FIGURE 7 is an enlarged cross sectional view taken generally along line7-7 of FIGURE 6.

Referring now to the drawing wherein the showings are for the purpose ofillustrating a preferred embodiment of the invention only and not forthe purpose of limiting same, FIGURE 1 shows a snow plowing mechanism Aincluding the forward blade B, a driving vehicle C, blade supportstructure D, and a blade B, a driving vehicle C, blade support structureD, and a blade lifting mechanism E. The plowing mechanism A is used, toclear snow or other debris from a roadway F having various obstructions,represented by a roadway fault G.

In accordance with the illustrated embodiment of the invention, theblade support structure D includes a forwardly extending support arm 10pivotally mounted on the vehicle at journal 12. The support arm ispivotally secured onto the blade by a structure, not shown, and a rigidstrut 14 holds the blade in its plowing position. By using the rigidstrut 14, blade B does not pivot around the support arm 10; therefore,the blade is considered a rigid blade. Of course, the support mechanismis provided with a device for changing the transverse angle of theblade, and it may also be provided with a normal tripping mechanism, ifdesired. However, the present invention generally eliminates the needfor a tripping mechanism. These actual structural support structures andturn-over structures do not form a part of the invention; therefore,they have been omitted for the purposes of simplicity.

The blade lifting mechanism E includes a support base having an uprightbeam 22. Pivotally secured on the top of the beam is a control arm 24which may be pivoted upwardly or downwardly by a cylinder 26 and ahydraulically controlled piston rod 28. As is normal practice, a chainor cable 30 connects the control arm 22 with the support arm 10 so thatthe blade may be raised or lowered by the chain upon movement of thecontrol arm. When lowered, the chain 30 has a certain amount of slack sothat the downwardmost position of the blade is generally determined bythe weight of the blade and the position of the roadway F. In operation,the blade lifting mechanism E drops the bade into its plowing position,as shown in FIGURE 1, and the vehicle C pushes the blade B along theroadway F to 'remove snow or other debris therefrom. As so fardescribed, the plowing mechanism A does not differ substantially fromknown mechanisms, and various changes in the described mechanisms may bemade without departing from the intended spirit and scope of the presentinvention.

Referring now to the blade B, the blade includes a generally curvilinearbody portion 40 having a lower terminal end 42, which is generallystraight. Vertical supports 44, only one of which is shown, extend alongthe back of the blade. Transverse supports 46, 48 extend transverselyacross the back of the blade to combine with the vertical support forrigidifying the body portion 40. In accordance with the presentinvention, the blade plowing edge 50 is formed from a strip 52 ofplastic material having characteristics, hereinafter described indetail. The plastic strip 52 includes a front surface 60, a rear surface62, a top edge 64, and a bottom edge portion 66. A transverselyextending plate 70 secures the strip 52 onto the terminal end 42 by useof spaced bolts 72. As shown in FIGURE 3, a rearward shoe 74, aplurality of which may be used, is secured onto the transverse support46 to ride above the roadway F. These shoes remain spaced from theroadway during normal use so that the weight of the blade B isessentially on the strip 52. In this manner, the blade B is stabilizedon the roadway.

In accordance with the preferred embodiment of the present invention,the strip 52 is formed from a cast polyurethane material, such asVulkollan. This material has sufiicient rigidity and flexibility at bothhigh and low temperatures so that the strip 52 extends forwardly like asteel member during normal plowing conditions. The hardness of the castpolyurethane should be in the range of 80-100 durometers. In practice,the strip 52 has a hardness of 90-95 durometers. In accordance with theinvention, the plastic material used for the plowing edge 50 has thecharacteristics as illustrated in FIGURE 5. In this figure, the strip 52is shown in its normal plowing position. The angle m represents themounting angle of the blade which can be termed the static plowing angleof the edge 50. In accordance with the invention, this angle isgenerally within the range of (25-65) Preferably, angle In is (30-35)Angle n is the normal plowing angle for the edge 50, or strip 52.Because of the physical characteristics of the plastic material, theangle 11 is generally equal to the angle m' minus (2-10). Preferably,the angle n is equal to the static plowing angle m minus approximately(2-5 In other words, tho material of strip 52 has sufficient rigidityand hardness that the Weight of the blade upon the strip changes itsstatic plowing position only a slight amount. This characteristic iscritical since a complete fold-back of the strip 52 would preclude anormal plowing angle close to the static plowing angle, which should bein the range of (25-65) with a vertical axis. In addition, the normalplowing angle 11 should be greater than approximately '(15-20)Preferably, the angle n is within the range of (30-35 which is also thepreferred range of the static plowing angle. It must be remembered thatthe weight of the blade itself is generally in the range of 50-75 poundsper linear foot of the plowing edge 50. This is a relatively high loadand only certain selected materials will absorb this load and plow snowor other debris within the angular limitations stated above andexhibited in FIGURE 5.

The material of the strip 52 also has sufficicnt flexibility to allowbackward deflection upon contacting an obstruction G, as shown inFIGURES 1 and 4, or an upwardly extending member such as a pin H, asshown in FIGURES 6 and 7. To define the physical characteristics thatare required to allow this particular function, it can be stated, inaccordance with the invention, that the strip 52 must have sufficientflexibility at low temperature to deflect backwardly at least an angle0, as shown in FIGURE 7, which angle is at least 90. This amount ofbackward deflection must be possible with a temperature of 20 F., ormore. The flexibility and memory of the plastic material must be suchthat after the obstruction has been passed the strip 52 returns to itsnormal plowing angle or position, as shown in FIGURE 3. It has beenfound that cast polyurethane having dimensions hereinafter describedwill possess such deflection and recovery properties when itstemperature approaches 70 F.

Referring now to FIGURES 3 and 6, in accordance with the preferredembodiment of the present invention, the strip 52 has a thickness awhich is in the range of inch, a length b which is in the range of 5-12feet, an unsupported width 0 which is in the range of 3-5 inches, and atotal width d which is in the range of 6-7 inches. The thickness a issomewhat dependent upon the length b. For instance, the length is 5-6.5feet the thickness is %1 inch, when the length is 7-9 feet the thicknessis 1 inch, and when the length is 10-12 feet, the thickness is 1%inches. In other words, the ratio of thickness to length for strip 52,in practice, is within the range of approximately 60-115. This ratio hasbeen developed empirically.

From the above discussion the characteristics of the material formingstrip 52 become readily apparent; therefore, various materials, otherthan cast polyurethane, which is used in practice, could be employed.Essentially, the strip 52 has physical characteristics which will allowthe strip to remain in a normal plowing angle n which is notsubstantially dilferent from the static plowing angle m. The weight ofthe blade and the normal unobstructed, plowing of snow does notdrastically change the outward facing angle of the plastic strip 52.However, upon meeting an obstruction, the blade flexes backwardly andrecovers to its original position. These properties may be stated invarious ways. The strip 52 does not buckle under the vertical weight ofthe blade, although it does flex backwardly upon meeting an obstruction.In addition, the material forming strip 52 has suflicient flexibilityand memory to allow at least a 90 backward deflection at 20 F. withsubstantially complete recovery and sufliciently rigid to support atleast 50 pounds per linear foot of the strip during normal, unobstructedplowing with less than approximately 10 backward deflection duringplowing. The plastic material has sufiicient rigidity to allow only aslight deflection of the strip 52 as the weight of the blade B isimposed thereon and a suflicient flexibility to allow the strip todeflect as the blade passes over an obstruction on a roadway.

This performance is completely different from the performance of anyblade heretofore used or suggested. For instance, referring to FIGURE 2,blade has a backwardly inclined plowing edge. This allows snow 82 toaccumulate under the blade during plowing. Consequently, the blade israised from the roadway F and eflicient plowing is diflicult. If arubber plowing edge or a plowing edge formed from a material not havingthe characteristics defined above were used, the same general conditionwould result. This is illustrated on the right of FIGURE 2. A rubberblade folds backwardly during plowing. This gives a squeegee action andcauses accumulation of snow 92 in front of the blade. In both instancesshown in FIGURE 2 the force vector V V of the snow against the blade isdirected substantially toward the rear of the blade. As shown in FIGURE5, with a plastic material having the characteristics defined in thisapplication, the force vector V is substantially up the inclined plowingedge 50 so that snow or other debris is forced onto the body portion ofthe blade by riding over the plowing edge 50 as it remains in a forwarddisposition. It is seen that the plowing action of the present inventionis entirely different to the plowing action created by either of theblades shown in FIGURE 2.

During experiments, a blade constructed in accordance with the presentinvention was driven into a pile of slag. The blade edge 50 remainedinclined outwardly, and it acted as a cutting edge. The blade wasprovided with the standard tripping mechanism; however, the resiliencyof the strip 52 absorbed the resulting shock, and the blade was nottripped. When a standard steel blade with the same mechanism was used,the tripping mechanism tripped the blade. This test indicates that thepresent invention is useful without a tripping mechanism to do heavyduty jobs, besides snow plowing.

The present invention has been described in connection with onestructural embodiment; however, it is appreciated that variousstructural embodiments may be used without departing from the intendedspirit and scope of the present invention as defined in the appendedclaims.

Having thus defined my invention, I claim:

1. In a plow of the type used to clear snow and debris from roadways andsimilar surfaces, said plow including a moldboard having an elongatedupper edge, an elon' gated horizontal lower edge and an inwardly curvedforward surface between said upper and lower edges, an elongated cuttingedge member attached to said moldboard adjacent said lower edge, saidcutting edge member having a thickness not substantially less thanthreefourths of an inch and projecting downwardly from said lower edgean unsupported free distance not substantially less than three inches,said cutting edge member having top and bottom edges and front and rearsurfaces, said rear surface intersecting said bottom edge at a corner,said cutting edge member extending forwardly and downwardly from saidlower edge of said moldboard with said corner contacting a surface to beplowed and with said front and rear surfaces inclined rearwardly fromsaid bottom edge to said top edge at an angle substantially less thanninety degrees with respect to a vertical plane passing through saidcorner, said cutting edge member being subjected to horizontal forcestending to deflect said bottom edge corner rearwardly and decrease therearward inclination angle of said front surface, a first horizontalforce being defined by friction acting between said bottom edge cornerand a roadway or the like as said plow is moved forwardly along aroadway with the weight of said moldboard pressing said bottom edgecorner against the roadway, a second horizontal force being defined bythe weight and resistance to movement of snow or debris acting againstsaid front surface, a third horizontal force being defined bysubstantially immovable obstructions projecting up from a roadway or thelike and acting against said front surface, said cutting edge memberbeing formed of elastomeric material havcing mechanical propertiessimilar to cast polyurethane of at least 70 durometer hardness andhaving sufiicient rigidity to prevent rearward deflection of said frontsurface to a vertical position under action of said first and secondforces so that said second force normally has a component actingupwardly along said front surface, said cutting edge member beingresiliently deformable so as to deform rearwardly under action of saidthird force to a position in which at least a portion of said frontsurface is facing downwardly and having sufiicient resilient memory forreturning to its original position when said third force is removed.

2. The plow of claim 1 wherein said front surface of said cutting edgemember slopes rearwardly from said bottom edge to said top edge at anangle not less than twenty-five degrees with respect to a vertical planepassing through said corner and said angle is reduced not greater thanten degrees when said cutting edge member deforms rearwardly underaction of said first and second forces.

3. The plow of claim 1 wherein said cutting edge member is deformablerearwardly under action of said third force at least ninety degrees attwenty degrees below zero Farenheit and automatically recovers to itsoriginal position when said third force is removed.

References Cited UNITED STATES PATENTS 2,061,585 11/1936 Meyer 37-422,866,774 12/1958 Price 260-775 3,002,213 10/1961 Lindstrom 15-2443,119,138 1/1964 Davis 15-236 3,126,652 3/1964 Reissinger 37-413,199,234 8/1965 Reissinger 37-42 OTHER REFERENCES Walker, Texin SolidUrethane Elastomers, in Rubber World, July 1961, pp. 76-77.

Waugaman & Jennings, Estanethermoplastic Polyurethanes, in Rubber World,July 1961, pp. 72-75.

ROBERT E. PULFREY, Primary Examiner E. H. EICKHOLT, Assistant ExaminerUS. Cl. X.R.

